This invention relates generally to delay circuits and in particular to a programmable delay circuit.
Delay circuits are used in computer systems and other digital circuitry to adjust timing signals for purposes of synchronization of different timing signals or data signals. Delay circuits may be analog delay circuits in which analog signals control the activation of delay elements, such as current-starved inverters, or digital delay circuits in which digital signals control delay elements. Conventional delay circuits include switchable delay steps that allow users or systems to adjust a delay output by the delay circuit. However, conventional delay circuits suffer from non-uniform delay steps. Engaging one step adjusts the delay by one value and engaging the next step adjusts the delay by another value that is not the same as the first value, resulting in non-linear and non-uniform delay changes.